Have nothing to do with command of the forces (4)
I believe the answer is:
shun
'have' is the definition.
The definition and answer can be both to do with communicating as well as being verbs in their base form.
Maybe you can see an association between them that I can't see?
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for shun that I've seen before include "Spurn; avoid" , "Deliberately have no contact with" , "Avoid, keep away from" , "Persistently avoid" , "Steer clear of" .)